Gatekeeper-
I used the J-13 Javelina Deluxe Hunting Call from the JavelinaHunter website. I went with the deluxe model over the regular one for 2 reasons: 1st I like wood better than plastic. 2nd because of the 'lifetime re-tune' policy. The same site has an excellent DVD on Javelina Hunting as well, which I purchased and passed it around to all of my buddy's before the trip.
From what I understand, yes, it is just a predator call. From my limited experience, the Javelina will only respond to a call if/when you are very close. They won't come over a long distance to a call. We only used the call when we spooked them durring a stalk and they usually came back. We also used it to 'attempt' to call in a coyote. He saw us and was troting away, we blew on the call and he stopped and looked at us, but he was way out of range and didn't come back towards us.
Hope this helps.
-Mack